The entry is based on data pertaining to the
vibrational states v_{8} ≤ 2 and
takes into account interactions between these states.
Interactions with states v_{4} = 1,
v_{7} = 1, and v_{8} = 3
were accounted for through spectroscopic parameters and
appropriate interaction parameters. The fit was described
in
(1) H. S. P. Müller, L. R. Brown, B. J. Drouin, J. C.
Pearson, I. Kleiner, R. L. Sams, K. Sung, M. H. Ordu,
and F. Lewen,
2015, J. Mol. Spectrosc. 312, 22.
Vibrational ground state data with ^{14}N hyperfine
splitting were taken from
(2) S. G. Kukolich, D. J. Ruben, J. H. S. Wang, and J. R. Williams,
1973, J. Chem. Phys. 58, 3155;
from
(3) S. G. Kukolich,
1982, J. Chem. Phys. 76, 97;
and from
(4) D. Boucher, J. Burie, J. Demaison, A. Dubrulle, J.
Legrand, and B. Segard,
1977, J. Mol. Spectrosc. 64, 290.
Additional, extensive data between 91 ans 790 GHz were
taken from
(5) G. Cazzoli and C. Puzzarini,
2006, J. Mol. Spectrosc. 240, 153.
Two K = 14 transitions were taken
from
(6) M. Šimecková, Š. Urban, U. Fuchs,
F. Lewen, G. Winnewisser, I. Morino, K.M.T. Yamada,
2004, J. Mol. Spectrosc. 226, 123.
Further extensive data up to 1.63 THz were reported
in (1) and in
(7) H. S. P. Müller, B. J. Drouin, and J. C. Pearson,
2009, Astron. Astrophys. 506, 1487.
The purely Kdependent terms were determined through
ΔK = 3 infrared loops
from
(8) R. Anttila, V.M. Horneman, M. Koivusaari, and
R. Paso,
1993, J. Mol. Spectrosc. 157, 198,
and from the interactions treated in (1).
The v_{8} = 1 data were mostly taken
from (1). Additional millimeter wave data come
from
(9) A. Bauer and S. Maes,
1969, J. Phys. (Paris) 30, 169.
The ν_{8} data were published
by
(10) M. Koivusaari, V.M. Horneman, and R. Anttila,
1992, J. Mol. Spectrosc. 152, 377.
The v_{8} = 2 data as well as the
2ν_{8} data were mostly taken from (1).
Additional data come from
(11) A. Bauer and S. Maes,
1969, C. R. Acad. Sci. Ser. B 268, 1569,
and from
(12) R. Bocquet, G. Wlodarczak, A. Bauer, and J. Demaison,
1988, J. Mol. Spectrosc. 127, 382.
Parameters of three higher vibrational states were
taken from
(13) A.M. Tolonen, M. Koivusaari, J. Schroderus,
S. Alanko, and R. Anttila,
1993, J. Mol. Spectrosc. 160, 554.
Vibrational identifiers in this and related entries are
0 for v = 0 (1 with HFS),
2 for v_{8} = 1, l = –1 (4 with HFS),
3 for v_{8} = 1, l = +1 (5 with HFS),
6 for v_{8} = 2, l = 0 (9 with HFS),
7 for v_{8} = 2, l = +2 (10 with HFS),
8 for v_{8} = 2, l = –2 (11 with HFS).
Transitions between vibrational states occur in the lower
energy entry.
The predictions should be reliable throughout.
Increasing caution is advised at higher K, i.e.,
higher than 12 for l = 0.
The rotational part of the partition function is complete
up to 500 K (J up to 140 and K up to 30).
Vibrational contributions have been considered in
the calculation of the partition function for states
up to about 1200 cm^{–1}.
Higher vibrational states contribute to less than
3.0 % at 300 K. Additional information on
vibrational states is also available.
The transition dipole moment was determined in (1).
